Poor feedback / response and no resolution

I bought a demo smartphone through Groupon. The Groupon site marketed the smartphone as an LTE capable phone. After buying the phone, I found out that it was not an LTE phone and did not have a USB3. charger in the box. I reported the matter through their automated email and I did not receive a response. I called a number and the consultant could not find my comments on their system. He advised I send an email which I did in 2015 and I did not receive a response. I followed up with them and no response. I followed up again in 2016 and finally received a response from a customer care consultant for which the response was not addressing and solving the problem. I followed up again through their automated email and did not receive a response. The automated response says they are experiencing a high volume of queries to deal with. This has been a terrible experience and totally unprofessional. I am really frustrated by how I have been treated and this is totally unacceptable. I've been advised by friends and family not to buy products from Groupon due to similar experiences of lack of response and resolution to the problem. Customers must ensure they are not left stranded like me!